1. Field of the Invention
This invention relates to resin foams and more particularly, to an impregnant which is suitably applied to open-cellular, soft resin foams which have been previously produced by any of known methods so as to impart desired physical properties to the resin foams.
2. Prior Art
Several methods of producing semi-rigid and rigid resin foams are known including a mechanical foaming method, a soluble matter mixing method, a gas pressure utilizing method, a foaming agent utilizing method and the like.
All of these methods are those in which resin foams are obtained to have a semi-rigidity or rigidity within a predetermined range. In order to obtain a product of desired properties it is essential to use a specific type of starting materials and a specific production process which depend on the type of a final product.
Accordingly, it is difficult to stepwise obtain from products of different degrees of rigidity which are intermediate between those of a semi-rigid product and a rigid product, so that their physical properties are naturally limited and thus a wide variety of foam products could not be obtained. In addition, rigid resin foams have never been produced in the form of open cells.